‘Shaking pig syndrome’ identified on Austrian farm
Scientists in Austria have identified a virus that causes a congenital tremor in piglets and can result in heavy losses to infected litters.
Dubbed shaking piglet syndrome, the virus resembles classical swine fever and causes extensive brain and spinal cord damage to infected piglets.
While the virus has only been reported on one farm following an outbreak in 2015, researchers at the University of Veterinary Medicine (Vetmeduni) in Vienna hope that by identifying the virus it will help them spot problem herds and develop a vaccine to control the disease.
In a study published in Emerging Infectious Diseases, the researchers said the diseased piglets on the infected farm in Austria were born with such severe shaking of the whole body that they were unable to suckle.
Although the outbreak stopped after seven months, the farm’s productivity was severely hit, with just 22.4 piglets weaned per sow/year, compared with the farm’s previous performance of 25.8 piglets.
Postmortems of the infected animals revealed severe brain and spinal cord damage, typical of the type observed with type A-11 congenital tremors. Older pigs on the farm did not show any symptoms.
Following investigations on the farm, the researchers ran a new type of diagnostic test that allowed them to identify a new pestivirus — a genus of virus associated with classical swine fever — as the cause of the shaking.
Provisionally called LINDA (lateral shaking inducing neuro-degenerative agent), the virus is closely related to the atypical porcine pestiviruses (APPVs) which were recently discovered in the United States.
However, the researchers said its closest relative is the Bungowallah virus, which was identified in Australia in 2003, and causes abortions, stillbirth and sudden deaths.
While the disease has only ever been confirmed on two pig units, it was responsible for the death of 50,000 animals and the farms never recovered from the losses.
Report co-author Benjamin Limp of the university’s Institute of Virology said the researchers detected the virus in the saliva and semen of mature pigs on the farm, leading them to believe the disease might be sexually transmitted.
The team is now developing further tests so they can find out whether the LINDA virus is present in other farms in Austria, and assess whether it poses a risk to the country’s pig breeding sector, Limp said.
Till Rümenapf, the head of the Institute, added: “Because it also infects the uterus of pregnant sows, the LINDA virus could disrupt the development of the piglets’ cerebral cortex, like infection with the Zika virus.
“However, we should remember that the closest genetic relative of our new virus is an Australian.”
Rümenapf said the early identification of LINDA was key to helping scientists and the pig sector develop strategies to deal with new pathogens which develop each year.
“Whereas diseases were previously not tackled until they were fairly widespread, we now try to understand the mechanism of infection as early as possible so that we can develop control strategies before things get out of hand,” he added.